She keeps using the word metabolism. The resting metabolisms of humans do not vary with much standard deviation from the mean. If she actually had a fast metabolism, it would manifest itself in something. She'd be twitching constantly, or running a fever. Energy cannot be created or destroyed; it has to go somewhere. I think a much more likely explanation would be that she has some weird mutation that causes food to go right through her with only a small fraction of it being absorbed through her intestines.

It's sad that she's STILL not happy with her body, which looks great to me. She should be careful, though -- just being thin isn't enough to protect against high cholesterol or diabetes if she's not eating well.

I have the same problem. I(35 y/o 5'9" male) want to get up to 160-165lb but can't get past 146lb no matter how much I eat or drink./My high metabolism might what's keeping me from growing a full beard, grey hair, and balding